Mixer motor not restarting

Blender Repair
1

Brand:Kitchen Aid
Model Number: KSM90 Stand Mixer
Main Symptom: mixer motor not starting
What happens & when: I replaced the speed control board, adjusted the low speed, turned the mixer off, snugged the jam nuts (2), replaced the bonnet, and switched the mixer on. The mixer did not, and with adjustment, will not turn on again. Might the phase board have failed? If so, why? Of not, what may be the problem? All wires are firmly attached.

Error Code (if any): none
Parts or tests already tried: none yet
Photos / video link:

2

See if this is of any help!

servicemanual-4177310-revc.pdf (2.4 MB)

3

When you try to start the mixer, does it hum at all or is it completely quiet?